All posts by John Ernest

What is The Heartbleed Bug…and what do you do next ?

The Heartbleed Bug

The Heartbleed Bug is a serious vulnerability in the popular OpenSSL cryptographic software library. This weakness allows stealing the information protected, under normal conditions, by the SSL/TLS encryption used to secure the Internet. SSL/TLS provides communication security and privacy over the Internet for applications such as web, email, instant messaging (IM) and some virtual private networks (VPNs).

The Heartbleed bug allows anyone on the Internet to read the memory of the systems protected by the vulnerable versions of the OpenSSL software. This compromises the secret keys used to identify the service providers and to encrypt the traffic, the names and passwords of the users and the actual content. This allows attackers to eavesdrop on communications, steal data directly from the services and users and to impersonate services and users.

Heartbleed Bug

What leaks in practice?

We have tested some of our own services from attacker’s perspective. We attacked ourselves from outside, without leaving a trace. Without using any privileged information or credentials we were able steal from ourselves the secret keys used for our X.509 certificates, user names and passwords, instant messages, emails and business critical documents and communication.

How to stop the leak?

As long as the vulnerable version of OpenSSL is in use it can be abused. Fixed OpenSSL has been released and now it has to be deployed. Operating system vendors and distribution, appliance vendors, independent software vendors have to adopt the fix and notify their users. Service providers and users have to install the fix as it becomes available for the operating systems, networked appliances and software they use.


Q&A

What is the CVE-2014-0160?

CVE-2014-0160 is the official reference to this bug. CVE (Common Vulnerabilities and Exposures) is the Standard for Information Security Vulnerability Names maintained by MITRE. Due to co-incident discovery a duplicate CVE, CVE-2014-0346, which was assigned to us, should not be used, since others independently went public with the CVE-2014-0160 identifier.

Why it is called the Heartbleed Bug?

Bug is in the OpenSSL’s implementation of the TLS/DTLS (transport layer security protocols) heartbeat extension (RFC6520). When it is exploited it leads to the leak of memory contents from the server to the client and from the client to the server.

What makes the Heartbleed Bug unique?

Bugs in single software or library come and go and are fixed by new versions. However this bug has left large amount of private keys and other secrets exposed to the Internet. Considering the long exposure, ease of exploitation and attacks leaving no trace this exposure should be taken seriously.

Is this a design flaw in SSL/TLS protocol specification?

No. This is implementation problem, i.e. programming mistake in popular OpenSSL library that provides cryptographic services such as SSL/TLS to the applications and services.

What is being leaked?

Encryption is used to protect secrets that may harm your privacy or security if they leak. In order to coordinate recovery from this bug we have classified the compromised secrets to four categories: 1) primary key material, 2) secondary key material and 3) protected content and 4) collateral.

What is leaked primary key material and how to recover?

These are the crown jewels, the encryption keys themselves. Leaked secret keys allows the attacker to decrypt any past and future traffic to the protected services and to impersonate the service at will. Any protection given by the encryption and the signatures in the X.509 certificates can be bypassed. Recovery from this leak requires patching the vulnerability, revocation of the compromised keys and reissuing and redistributing new keys. Even doing all this will still leave any traffic intercepted by the attacker in the past still vulnerable to decryption. All this has to be done by the owners of the services.

What is leaked secondary key material and how to recover?

These are for example the user credentials (user names and passwords) used in the vulnerable services. Recovery from this leaks requires owners of the service first to restore trust to the service according to steps described above. After this users can start changing their passwords and possible encryption keys according to the instructions from the owners of the services that have been compromised. All session keys and session cookies should be invalided and considered compromised.

What is leaked protected content and how to recover?

This is the actual content handled by the vulnerable services. It may be personal or financial details, private communication such as emails or instant messages, documents or anything seen worth protecting by encryption. Only owners of the services will be able to estimate the likelihood what has been leaked and they should notify their users accordingly. Most important thing is to restore trust to the primary and secondary key material as described above. Only this enables safe use of the compromised services in the future.

What is leaked collateral and how to recover?

Leaked collateral are other details that have been exposed to the attacker in the leaked memory content. These may contain technical details such as memory addresses and security measures such as canaries used to protect against overflow attacks. These have only contemporary value and will lose their value to the attacker when OpenSSL has been upgraded to a fixed version.

Recovery sounds laborious, is there a short cut?

After seeing what we saw by “attacking” ourselves, with ease, we decided to take this very seriously. We have gone laboriously through patching our own critical services and are in progress of dealing with possible compromise of our primary and secondary key material. All this just in case we were not first ones to discover this and this could have been exploited in the wild already.

How revocation and reissuing of certificates works in practice?

If you are a service provider you have signed your certificates with a Certificate Authority (CA). You need to check your CA how compromised keys can be revoked and new certificate reissued for the new keys. Some CAs do this for free, some may take a fee.

Am I affected by the bug?

You are likely to be affected either directly or indirectly. OpenSSL is the most popular open source cryptographic library and TLS (transport layer security) implementation used to encrypt traffic on the Internet. Your popular social site, your company’s site, commerce site, hobby site, site you install software from or even sites run by your government might be using vulnerable OpenSSL. Many of online services use TLS to both to identify themselves to you and to protect your privacy and transactions. You might have networked appliances with logins secured by this buggy implementation of the TLS. Furthermore you might have client side software on your computer that could expose the data from your computer if you connect to compromised services.

How widespread is this?

Most notable software using OpenSSL are the open source web servers like Apache and nginx. The combined market share of just those two out of the active sites on the Internet was over 66% according to Netcraft’s April 2014 Web Server Survey. Furthermore OpenSSL is used to protect for example email servers (SMTP, POP and IMAP protocols), chat servers (XMPP protocol), virtual private networks (SSL VPNs), network appliances and wide variety of client side software. Fortunately many large consumer sites are saved by their conservative choice of SSL/TLS termination equipment and software. Ironically smaller and more progressive services or those who have upgraded to latest and best encryption will be affected most. Furthermore OpenSSL is very popular in client software and somewhat popular in networked appliances which have most inertia in getting updates.

What versions of the OpenSSL are affected?

Status of different versions:

  • OpenSSL 1.0.1 through 1.0.1f (inclusive) are vulnerable
  • OpenSSL 1.0.1g is NOT vulnerable
  • OpenSSL 1.0.0 branch is NOT vulnerable
  • OpenSSL 0.9.8 branch is NOT vulnerable

Bug was introduced to OpenSSL in December 2011 and has been out in the wild since OpenSSL release 1.0.1 on 14th of March 2012. OpenSSL 1.0.1g released on 7th of April 2014 fixes the bug.

How common are the vulnerable OpenSSL versions?

The vulnerable versions have been out there for over two years now and they have been rapidly adopted by modern operating systems. A major contributing factor has been that TLS versions 1.1 and 1.2 came available with the first vulnerable OpenSSL version (1.0.1) and security community has been pushing the TLS 1.2 due to earlier attacks against TLS (such as the BEAST).

How about operating systems?

Some operating system distributions that have shipped with potentially vulnerable OpenSSL version:

  • Debian Wheezy (stable), OpenSSL 1.0.1e-2+deb7u4
  • Ubuntu 12.04.4 LTS, OpenSSL 1.0.1-4ubuntu5.11
  • CentOS 6.5, OpenSSL 1.0.1e-15
  • Fedora 18, OpenSSL 1.0.1e-4
  • OpenBSD 5.3 (OpenSSL 1.0.1c 10 May 2012) and 5.4 (OpenSSL 1.0.1c 10 May 2012)
  • FreeBSD 10.0 – OpenSSL 1.0.1e 11 Feb 2013
  • NetBSD 5.0.2 (OpenSSL 1.0.1e)
  • OpenSUSE 12.2 (OpenSSL 1.0.1c)

Operating system distribution with versions that are not vulnerable:

  • Debian Squeeze (oldstable), OpenSSL 0.9.8o-4squeeze14
  • SUSE Linux Enterprise Server
  • FreeBSD 8.4 – OpenSSL 0.9.8y 5 Feb 2013
  • FreeBSD 9.2 – OpenSSL 0.9.8y 5 Feb 2013
  • FreeBSD Ports – OpenSSL 1.0.1g (At 7 Apr 21:46:40 2014 UTC)

How can OpenSSL be fixed?

Even though the actual code fix may appear trivial, OpenSSL team is the expert in fixing it properly so latest fixed version 1.0.1g or newer should be used. If this is not possible software developers can recompile OpenSSL with the handshake removed from the code by compile time option -DOPENSSL_NO_HEARTBEATS.

Should heartbeat be removed to aid in detection of vulnerable services?

Recovery from this bug could benefit if the new version of the OpenSSL would both fix the bug and disable heartbeat temporarily until some future version. It appears that majority if not almost all TLS implementations that respond to the heartbeat request today are vulnerable versions of OpenSSL. If only vulnerable versions of OpenSSL would continue to respond to the heartbeat for next few months then large scale coordinated response to reach owners of vulnerable services would become more feasible.

Can I detect if someone has exploited this against me?

Exploitation of this bug leaves no traces of anything abnormal happening to the logs.

Can IDS/IPS detect or block this attack?

Although the content of the heartbeat request is encrypted it has its own record type in the protocol. This should allow intrusion detection and prevention systems (IDS/IPS) to be trained to detect use of the heartbeat request. Due to encryption differentiating between legitimate use and attack can not be based on the content of the request, but the attack may be detected by comparing the size of the request against the size of the reply. This seems to imply that IDS/IPS can be programmed to detect the attack but not to block it unless heartbeat requests are blocked altogether.

Has this been abused in the wild?

We don’t know. Security community should deploy TLS/DTLS honeypots that entrap attackers and to alert about exploitation attempts.

Can attacker access only 64k of the memory?

There is no total of 64 kilobytes limitation to the attack, that limit applies only to a single heartbeat. Attacker can either keep reconnecting or during an active TLS connection keep requesting arbitrary number of 64 kilobyte chunks of memory content until enough secrets are revealed.

Is this a MITM bug like Apple’s goto fail bug was?

No this doesn’t require a man in the middle attack (MITM). Attacker can directly contact the vulnerable service or attack any user connecting to a malicious service. However in addition to direct threat the theft of the key material allows man in the middle attackers to impersonate compromised services.

Does TLS client certificate authentication mitigate this?

No, heartbeat request can be sent and is replied to during the handshake phase of the protocol. This occurs prior to client certificate authentication.

Does OpenSSL’s FIPS mode mitigate this?

No, OpenSSL Federal Information Processing Standard (FIPS) mode has no effect on the vulnerable heartbeat functionality.

Does Perfect Forward Secrecy (PFS) mitigate this?

Use of Perfect Forward Secrecy (PFS), which is unfortunately rare but powerful, should protect past communications from retrospective decryption. Please seehttps://twitter.com/ivanristic/status/453280081897467905 how leaked tickets may affect this.

Can heartbeat extension be disabled during the TLS handshake?

No, vulnerable heartbeat extension code is activated regardless of the results of the handshake phase negotiations. Only way to protect yourself is to upgrade to fixed version of OpenSSL or to recompile OpenSSL with the handshake removed from the code.

Who found the Heartbleed Bug?

This bug was independently discovered by a team of security engineers (Riku, Antti and Matti) atCodenomicon and Neel Mehta of Google Security, who first reported it to the OpenSSL team. Codenomicon team found heartbleed bug while improving the SafeGuard feature in Codenomicon’s Defensics security testing tools and reported this bug to the NCSC-FI for vulnerability coordination and reporting to OpenSSL team.

What is the Defensics SafeGuard?

The SafeGuard feature of the Codenomicon’s Defensics security testtools automatically tests the target system for weaknesses that compromise the integrity, privacy or safety. The SafeGuard is systematic solution to expose failed cryptographic certificate checks, privacy leaks or authentication bypass weaknesses that have exposed the Internet users to man in the middle attacks and eavesdropping. In addition to the Heartbleed bug the new Defensics TLS Safeguard feature can detect for instance the exploitable security flaw in widely used GnuTLS open source software implementing SSL/TLS functionality and the “goto fail;” bug in Apple’s TLS/SSL implementation that was patched in February 2014.

Who coordinates response to this vulnerability?

NCSC-FI took up the task of reaching out to the authors of OpenSSL, software, operating system and appliance vendors, which were potentially affected. However, this vulnerability was found and details released independently by others before this work was completed. Vendors should be notifying their users and service providers. Internet service providers should be notifying their end users where and when potential action is required.

Is there a bright side to all this?

For those service providers who are affected this is a good opportunity to upgrade security strength of the secret keys used. A lot of software gets updates which otherwise would have not been urgent. Although this is painful for the security community, we can rest assured that infrastructure of the cyber criminals and their secrets have been exposed as well.

Where to find more information?

This Q&A was published as a follow-up to the OpenSSL advisory, since this vulnerability became public on 7th of April 2014. The OpenSSL project has made a statement athttps://www.openssl.org/news/secadv_20140407.txt. NCSC-FI published an advisory athttps://www.cert.fi/en/reports/2014/vulnerability788210.html. Individual vendors of operating system distributions, affected owners of Internet services, software packages and appliance vendors may issue their own advisories.

References

4 Beeps Coming From Your Computer – The Solution

I’ve had an annoying 4 short beeps coming from two different  PC’s for days now (Read on – it’s fixed) and I couldn’t figure what was causing it. I’d even timed it to approximately  every 45 seconds and it was driving me nuts. I’d just have to turn the speakers off. Not good.

This started happening on my old PC first and I did the Googling and came up with a ‘System Timer Error’ or a memory fault.

computer 4 short beeps

As the PC was old in any case, I took advantage of the opportunity to get a new Windows 8 PC. It arrived, plugged it in, up and running and hey, problem solved, no beeps!

Then literally 2 days ago, it started up again, so same ol’ Googling and same ol’ answers, but how could TWO completely different PC’s (The old one was a Windows 2008 Server) develop the same hardware fault ?

I went to the forums for the new PC manufacturer, and it was suggested I ran MEMTEST to check the RAM, which I did (all fine) and I was trying to think what the common element could be between the two PC’s. Since they’re networked I decided to run a virus scan to check (again, all fine) so then I started looking at what was running on the PC.

The inconsistency in the Motherboard/Memory theory was that the machine worked perfectly well and it only happened in Windows.

I’ll short circuit here and say that when I closed down Chrome, the beeping stopped; to confirm I opened it again and the beeping came back – every 45 seconds, beep-beep-beep-beep!

I use quite a few Chrome extensions and it was a process of elimination that led me to Snooze Your Email for Gmail.

Clicking on the options and unchecking ‘Notification Sound’ fixed it

4-beeps-on-pc

I’ve since read the reviews on this in the Chrome Web Store and I’m not the only one who’s got this. It looks like the Developer has withdrawn it www.jasonsavard.com so I’m going back to Boomerang for Gmail – they’ve got a Free version but the personal at $ 4.99 is probably the best value.

Anyway, hope this helps someone avoid shelling out for a new motherboard or PC – the simple rule is that if there is a hardware fault on the computer accompanied by four beeps, the PC is unlikely to start; if it starts normally, then look at what’s happening in your applications.

Beep Beep!

A Good Bet for The Grand National (Not a Tip!)

So Grand National Day is finally here. If you’re like me, then this is the one day of the year when you’ll be placing a bet; and if you’re like me, you’ll haved saved up a years potential betting for one day when you can go at it with some real cash and look to making some real money….which brings me back to my first big win, back in 1988.

The story actually starts a week earlier, on the Easter Monday; we’d driven to Banbury on a rainy Bank Holiday just for something to do; it was about a 30 minute drive along the A41 but was definitely more provincial than where we’d left. We arrived and the rain hadn’t stopped and it was lunchtime when we spotted a cosy looking Italian restaurant with parking outside (not such a luxury then…).

The restaurant was empty and after a superb meal and a bottle of wine and watching the rain stop, we decided to venture out and explore Banbury.

Well, we managed less than 100 yards before the heavens opened up again, and the nearest available shelter was a Ladbrokes bookmakers shop, so we dived in the doorway, swapping rain and cold for warmth and cigarette smoke. Now this wasn’t an unfamiliar environment for me, but for my more attractive female companion, it was slightly unusual. Anyway, after the stares subsided and the rain continued, we decided that we’d stay for while, and I thought it was only polite to look at the race-form papers on the wall.

As I began my earnest search, I became aware of someone very close to me and as I looked round, a small chap muttered to me in a broad Irish accent “You could do a lot worse than put some money on Rhyme and Reason…” and he just walked away over to the counter, where he took out £200 and placed his bet. Now I’d always thought it more ‘noble’ to make my own selection, but then I also believed in following the money so I swiftly followed with my £ 20 win, Rhyme and Reason, Irish Grand National.

Twenty minutes later, the horse romps home at 6 to 1, netting me a tidy £ 120 profit! (less tax) – best rainy day in a betting shop I’d ever had.

Fast forward to April 9th and the Grand National at Aintree.

I do like a little excitement with my Grand National Bet, so here’s what I do

  1. Pick 4 horses (my own selection criteria)
  2. Back them all to win
  3. Bet every forecast combination
  4. Bet every tricast combination
  5. …and usually the bookies throw in “All 4, in any order”

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I’m not saying this is clever, skilled or anything other than what I consider a good fun (and potentially lucrative) bet and I invariably get a good run for my money.

This particular year, I had selected

  • Rhyme and Reason
  • Durham Edition
  • West Tip
and a fourth horse who I’ve completely forgotten…

If you’d like to see the race, here it is – fast forward if you want to!

The result

1st Rhyme and Reason

2nd Durham Edition

…and West Tip was 4th!

I can still recall the feeling in the final furlong knowing that it wasn’t a question of ‘if’ I won but ‘how much’ I was going to win depending on who won.

Anyway, after I’d calmed down from my victory dance, I went to the local bookmakers and queued with everyone else collecting their winnings.

When it was my turn at the counter, the clerk took my slip and ruffled through the pile in front of her; she found mine and looked at me, and said “One moment. Sir”.

The Manager came over and looked at me again and said “…if you’d like to come through here…”. I wondered what might be wrong as he opened the door to the office and led me to a chair.

I sat down and he gave me my slip back and £ 77.

“I’ll just get £ 900 from the safe, if you can wait a moment”

Well, I wanted to laugh out loud – the eyes were looking at me from over the counter now, as he counted out the £900 for me and put it into a big brown envelope. I could hardly contain myself as I walked out, and immediately broke into a run outside to get back and tell my family.

That was £ 977 for a £ 5 bet. Not bad.

Can you imagine what it would have been if West Tip had made it to third ???

I’ve had a few more winners since, but nothing like that.

Maybe it’s my time again this year.